This invention relates to a motor bicycle having an engine at a central lower portion thereof and having a space sufficient for locating a box-like member in which a helmet or the like can be started.
A driver or rider who drives a motor bicycle usually wears a helmet on his head or is obliged to do so for security sake, and the helmet is usually left on or with the motor bicycle when he leaves from the motor bicycle at a parking time, for example. However, a conventional motor bicycle is not provided with any specific equipment for accommodating the helmet in a motor bicycle body, so that the rider or driver is obliged to bring the helmet or lock it to the motor bicycle when he leaves therefrom.
In a certain conventional technique, there is provided a motor scooter in which a stepped portion is arranged on a downwardly curved portion between a handle mechanism and a seat and a space sufficient for accommodating the helmet is defined at the lower portion of the seat by covering with an outer body with the seat as a cover for the space (for example, as disclosed in the Japanese Patent Laid-open Publication Nos. 154964/1985 or 282178/1986).
However, with a usual type motor bicycle in which the engine is mounted at the lower portion of the motor bicycle body, since a ride-on type seat is utilized, it is difficult to design the lower portion of the seat to have a wide lateral width and also to provide a space below the seat because the wheels of the motor bicycle have relatively large diameters in comparison with those of the motor scooter. Thus, with the conventional motor bicycle with an engine loaded at the central lower portion of the body, it is difficult to ensure a space for accommodating the helmet below the seat or in another portion of the motor bicycle body. Accordingly, when the rider leaves the motor bicycle, the helmet is left for example by hanging it from a portion of the motor bicycle body or he must carry about the helmet for preventing the helmet from being robbed, thus being inconvenienced.
Japanese Utility Model Publication No. 3572/1988 discloses a motor bicycle provided with a box for accommodating a helmet between a head tube and a seat by downwardly bending a body frame. However, the downward bending of the body frame provides problems on the rigidity thereof and the manufacturing, such as by a molding method, of the same. Moreover, when the motor bicycle is running, a driving stress is largely given to a portion joining the upper portion of the body frame and the head tube, and therefore, it is not desired to bend downwardly the body frame for bearing such driving stress.